1. Field of the Invention
The invention relates to allocation of assets to interconnected devices. More specifically, the invention relates to allocating a particular asset to devices of a storage system based on a capacity of the asset and a need for the asset by the devices.
2. Discussion of the Related Art
Systems often use a plurality of similar devices interconnected for performing desired functions. For example, a storage system can have a plurality of hard disk drives (“disks”) connected to a communication medium for storing data. In such a storage system, a master device operably controls the disks according to a particular storage system design. Each device connected to the communication medium has access to one or more assets of the system. An example of one such asset includes power from a power supply configured within the system.
Devices connected to the communication medium utilize these assets according to their particular needs. At certain times, some devices require more of a certain asset than at other times. For example, during a power-on-reset of a storage system, disks of the storage system begin turning, or “spin-up”, so that a host computer system may access data from the disks. During spin-up, disks require more current than they do to sustain spinning. However, as such a storage system powers on and resets, the combined current requirements of the disks spinning up often exceed a capacity that a power supply is capable of supplying. Thus, at certain times, devices require more of a particular asset than is presently available.
One solution to compensate for a lack of asset capacity within a system would be to simply increase the overall capacity of the asset. For example, a system could be configured to include a larger power supply to compensate for extra power that is required by devices during a power-on-reset or when many devices simultaneously spin-up. However, many devices do not persist in their demands for additional asset capacity. For example, as noted, once up to speed, rotating disk drives require less power. An implementation of the larger asset often results in useless and extraneous capacity during normal “steady-state” operation. Furthermore, as technology advances, it is often a design goal in many systems to decrease component size in order to accommodate flexibility in system design and in system use. Accordingly, increasing the physical size of an asset simply to increase the capacity contradicts goals of size minimization.
Another solution requires each device to timely operate with respect to the asset. For example, as a storage system is powered on, disks of the storage system spin-up in a timing sequence such that no combination of disk spin-ups exceeds the capacity of the power supply. However, timing each device of a system to utilize an asset often requires use of an intelligent controller to manage the timing. Such an intelligent controller would monitor each device to determine when a particular device operates in a mode that requires less of the asset. The intelligent controller, while useful in time management applications, increases the complexity of the system. Again, as design goals seek to simplify systems and hence shrink system sizes, the addition of an intelligent controller controverts those goals by increasing the complexity and size of the system.
It is evident from the above discussion that there is an ongoing need to provide improved system asset allocation to devices, particularly to those connected to a system communication medium, such as a device loop.